Suspected hepatitis cases were identified through an established active hepatitis surveillance system. The sentinels of the system comprised all the healthcare facilities in the field. Suspected hepatitis was defined as when patients presented with systemic symptoms such as fatigue and/or loss of appetite for more than 3 days with alanine aminotransferase (ALT) exceeding 2.5 fold upper limit of normal range (ULN). Paired sera were obtained from these patients at the time of presentation and 2-6 weeks later. Sera were tested for the HEV antibodies and HEV-RNA.